1. Field of the Invention
The present invention relates to an inkjet recording apparatus which performs recording by discharging ink to a recording material from recording means mounted on a reciprocating carriage.
2. Description of the Related Art
In a direction orthogonal to a direction in which recording materials such as a recording sheet of paper and a plastic thin plate are conveyed, a serial scan type recording apparatus performs main scan through a recording portion. In the serial scan type recording apparatus, an image is recorded with recording means (recording head) mounted on a carriage which moves along the recording material, the recording material is conveyed by a predetermined amount after recording of one line, and the image of the next line is recorded onto the recording material which is stopped again. The above operations are repeated, thereby recording onto the whole recording material. In the inkjet recording apparatus, one of such serial scan type recording apparatuses, which performs the recording by discharging the ink from the recording means, the recording means is easily made compact, a fine image can be recorded at high speed, and the recording can be performed to a sheet of plain paper with no special process. Further, the inkjet recording apparatus has advantages in that running cost is low, noise is little because of non-impact type recording method, and a color image is easily recorded with multi-color ink.
In the inkjet recording apparatus, when the ink in an ink tank runs out as a result of the recording, the ink tank is replaced with a new ink tank, and the ink is refilled into a flow path extending to the ink discharge portion. Further, in the inkjet recording apparatus, it is necessary to perform a recovery process of removing foreign matters such as adhesive ink near a discharge port and bubbles in the recording means. Namely, in order to stabilize an ink discharging action of the recording means to obtain good image quality, the inkjet recording apparatus generally has a recovery mechanism unit (cleaning mechanism unit) which maintains and recovers ink discharging performance of the recording means. The recovery mechanism unit usually includes a cap, suction recovery means, and wiping means. The discharge ports are covered with the cap by closely contacting a discharge port surface of the recording means. The suction recovery means sucks the thickened ink in the discharge port and the waste ink in the cap by introducing negative pressure into the cap. The wiping means cleans the discharge port surface by wiping the ink adhering to the discharge port surface with a wiper.
FIG. 12 is a front view showing a conventional recovery mechanism unit while the cap is opened, FIG. 13 is a front view showing the recovery mechanism unit shown in FIG. 12 while the capping state is partially broken away, and FIG. 14 a front view showing the conventional recovery mechanism unit of FIG. 12 while a cap slider (slide member) is fixed by a lock lever. In FIGS. 12 to 14, a carriage 126 on which a recording head 123 is mounted, moves along the recording material. The carriage 126 is movably guided and supported by guide rails 101a and 101b which are placed in a chassis 101 of an apparatus main body. A part of a timing belt 103 is coupled to the carriage 126. The carriage 126 reciprocates by drive force transmitted from a carriage motor 102 fixed to the chassis 101, through the timing belt 103.
On the base side of the apparatus main body, a recovery mechanism unit 108 is arranged at a position opposite the recording head 123 mounted on the carriage 126. A cap 104, with which a discharge port surface of the recording means is covered, is provided in the recovery mechanism unit 108. The cap 104 prevents the ink near the discharge port from adhering or thickening in a recording standby state. Also, the cap 104 sucks and recovers clogging of the discharge port by sucking that the ink from the discharge port by means of the negative pressure introduced from a negative-pressure generating source such as a pump. The cap 104 is made of a rubber material or the like having elasticity. The cap 104 is held by a cap holder 105. The cap holder 105 is mounted so as to be able to slide vertically with respect to a cap slider 106. A cap spring 107 is attached between the cap holder 105 and the cap slider 106.
A shaft portion 106a of the cap slider 106 is movably guided and supported along a cam surface (shown by broken lines) provided in a base portion of the apparatus main body. An abutting surface 106b which can abut onto a side face of the carriage 126 is provided in the cap slider 106. After the carriage 126 makes an entry into the recovery mechanism unit 108 to abut onto the abutting surface 106b, the cap slider 106 can follow the movement of the carriage 126. A lock lever 111 which fixes the cap slider at a predetermined position is attached to the cap slider 106. A lock lever spring 109 is provided between an end portion of the lock lever 111 and the apparatus main body side. When the carriage 126 is not located at the recovery mechanism unit 108, the cap slider 106 is held at a predetermined standby position by an action of the lock lever spring 109.
In the recovery mechanism unit 108 having the above-described configuration, when the carriage 126 makes the entry into the recovery mechanism unit, the side face of the carriage 126 abuts on the abutting surface 106b of the cap slider 106, which allows the cap slider 106 to follow the movement of the carriage 126 to be moved (slid). When the carriage 126 further makes the entry into a deeper portion of the recovery mechanism unit 108, the cap slider 106 is gradually lifted to the recording means side by the action of the cam surface (shown by broken line) on the apparatus main body side. Therefore, the cap 104 abuts onto the discharge port surface of the recording head 123, and the cap becomes a capping state. In the capping state, the cap 104 closely contacts the discharge port surface of the recording head by the action of spring pressure of the cap spring 107. Thus, the cap is in the standby state while being in the capping state, which allows the discharge ports and the discharge port surface of the recording head 123 to be protected.
One end of a suction tube 110 is connected to the cap 104 through the cap holder 105, and the other end of the suction tube 110 is connected to a suction pump. Accordingly, the ink can be sucked by the negative pressure generated in the cap 104 by operating the suction pump while the cap is in the capping state. The ink suction is a suction recovery process of eliminating the clogging of the discharge port, and the ink suction is one of main functions of the recovery mechanism unit 108.
When the moving direction of the carriage 126 is reversed to be moved in the direction in which the carriage 126 retracts from the recovery mechanism unit 108, the cap 104 retracts gradually from the discharge port surface to become an opened state, while the cap slider 106 is moved in synchronization with the carriage 126. Before the carriage 126 starts its reverse movement, the lock lever 111 is subject to a clockwise torque about a shaft 106a of the cap slider 106 by the action of the lock lever spring 109, so that a leading end of the lock lever is latched at the position shown in FIG. 14 fixing/latching portion, and the lock lever 111 is held and stopped at the position. When the carriage 126 is further moved in the direction in which the carriage 126 retracts while the lock lever 111 is latched, the cap slider 106 whose shaft 106a holds the lock lever 111 is also held by the apparatus main body side to release the synchronous movement between the cap slider 106 and the carriage 126, which allows only the carriage 126 to start the movement toward a recording area.
A wiper 112 which wipes the discharge port surface 125 is mounted on the cap slider 106. In the state shown in FIG. 14, the leading end of the wiper 112 is arranged at the position where the wiper 112 comes into contact with the discharge port surface 125. Therefore, when the carriage 126 is further moved in the direction in which the carriage 126 retracts, each discharge port array provided in the discharge port surface 125 is sequentially wiped by the wiper 112, which allows the foreign matters such as the adhesive ink near the discharge port to be removed. The wiper 112 is formed by a plate-shaped member made of a rubber material or the like having elasticity. When the carriage 126 is moved to the position where the wiper 112 ends the wiping, a releasing portion 126a provided in the carriage abuts onto the leading end of the lock lever 111 to push down the lock lever in the counterclockwise direction, which releases the latching between the lock lever 111 and the latching portion of the base portion. Then, spring force of the lock lever spring 109 acts on the cap slider 106 again, and the cap slider 106 is held after the cap slider 106 is moved to the standby position shown in FIG. 12.
U.S. Pat. No. 6,109,725 discloses a mechanism, in which a wiper holder for holding the wiper is attached while one end of the wiper holder acts as a rotating axis, the other end being urged by the spring, and the carriage abuts onto the wiper holder to keep an insertion amount (overlap amount, interference depth) of the wiper constant with respect to the discharge port surface.
In the configuration shown in FIGS. 3 and 11 of Japanese Patent Application Laid-Open No. 2000-15832, when the carriage is moved to the recovery mechanism unit, the wiper holder is moved in the direction in which the wiper holder enters the discharge port surface by the followed movement of the cap slider. Then, an abutting portion provided in the cap holder abuts onto the carriage to keep the insertion amount of the wiper constant during the wiping. Thus, the process of cleaning the recording head can be performed by the movement of the carriage and the action of the recovery mechanism unit.
However, in the above-described conventional techniques, when an unavoidable convex part (protrusion part) or a concave part is formed at the end portion of each discharge port array in the recording means due to a production method or an internal structure, the wiper runs on the convex part or the wiper is hooked on the concave part, which results in problems in that wiping performance is decreased and the cleaning cannot sufficiently be performed.
FIG. 15 is a front view showing a relative positional relationship between the wiper and the recording means when the recording mechanism unit (carriage unit) is obliquely held in the conventional inkjet recording apparatus. FIG. 16 is an explanatory view illustrating each discharge port array of the recording means and a wiper configuration and arrangement when the wiper wipes respective discharge port arrays and the convex parts of the discharge port arrays. FIGS. 17A and 17B are explanatory views showing the state in which the wiping is performed while the wiper avoids the convex parts of a color discharge port unit in the discharge port surface of the recording means. Referring to FIGS. 16, 17A and 17B, the wiping action in the case where the convex parts exist on the discharge port surface of the recording means will be described below. In FIGS. 15, 16, 17A and 17B, color discharge port arrays 123a and a black discharge port array 123b are formed in the discharge port surface 125 of the recording head 123, and convex parts 128 are formed at end portions of the discharge port arrays 123a and 123b due to the production method. As shown in FIG. 16, wipers 112a and 112b which correspond to the discharge port arrays 123a and 123b are provided in the recovery mechanism unit.
The color discharge port away 123a will mainly be described. As shown in FIGS. 17A and 17B, notches are provided in the wiper 112a so as to avoid the convex parts 128. This is because, as shown in FIG. 17B, when the wiper 112a runs on the convex part 128, a space (gap) is generated between the discharge port surface and the wiper 112a, hindering appropriate wiping. In the recording head 123, it is necessary that the relative position between the discharge port surface and the wiper 112a is corrected with high accuracy in order that a wiping portion of the wiper 112a does not run on the convex parts 128 and the whole area of the discharge port array 123a can securely be wiped. However, in the conventional wiping mechanism shown in FIGS. 12 to 14, the relative positional relationship between the carriage 126 including the recording means and the wiper 112 depends on a size and assembly accuracy of each component in all the directions. Therefore, in order that the wiper 112a securely wipes the whole area of the discharge port away 123a without running on the convex part 128 of the discharge port surface, it is necessary to improve the accuracy of each component, which increases the cost.
In the configuration disclosed in U.S. Pat. No. 6,109,725, when the position of the recording head fluctuates in a sheet thickness direction, parallelism cannot be maintained at a contact surface between the wiper 112 and the discharge port surface of the recording head 123. Further, in the recording apparatus having a sheet-gap adjusting mechanism in which a distance between the recording head 123 and the recording sheet is changed by tilting the carriage with respect to a guide rail bib, the parallelism cannot be maintained at the contact surface either. When the convex part 128 is formed on the discharge port surface of the recording head, the wiper 112 runs on the convex part 128, so that the discharge port surface of the recording head 123 cannot sufficiently be wiped. In the configuration disclosed in Japanese Patent Application Laid-Open No. 2000-15832, the relative position between the recording head and the wiper is uniformly controlled only in the wiper insertion amount direction, and the relative position in the array direction of the discharge port away depends on the component accuracy and the attachment accuracy. Accordingly, the decrease in assembly accuracy cannot be avoided because of an accumulative error of the component accuracy, and the cost is remarkably increased when the decrease in assembly accuracy is improved.